Search results for "P21"

KRAS mutations and sensitivity to anti-EGFR monoclonal antibodies in metastatic colorectal carcinoma: an open issue.

2009

Background: Cetuximab and panitumumab, mAbs targeting EGFR, are registered for metastatic colorectal carcinoma (mCRC) patients whose tumors express EGFR as determined by immunohistochemistry. However, this method is not predictive of treatment efficacy. KRAS, the human homolog of the Kirsten rat sarcoma-2 virus oncogene, encodes a small G-protein that functions downstream of EGFR-induced signalling. Objective/Methods: To examine KRAS mutations as predictive factors of response to anti-EGFR mAbs using recently published data. Results/conclusions: Several retrospective studies show that efficacy of these mAbs is confined to patients with wild type KRAS and genotyping of tumors should be consi…

Integrative genomic and proteomic analyses identify targets for Lkb1 deficient metastatic lung tumors

2010

SummaryIn mice, Lkb1 deletion and activation of KrasG12D results in lung tumors with a high penetrance of lymph node and distant metastases. We analyzed these primary and metastatic de novo lung cancers with integrated genomic and proteomic profiles, and have identified gene and phosphoprotein signatures associated with Lkb1 loss and progression to invasive and metastatic lung tumors. These studies revealed that SRC is activated in Lkb1-deficient primary and metastatic lung tumors, and that the combined inhibition of SRC, PI3K, and MEK1/2 resulted in synergistic tumor regression. These studies demonstrate that integrated genomic and proteomic analyses can be used to identify signaling pathw…

The Long and Winding Road to Useful Predictive Factors for Anti-EGFR Therapy in Metastatic Colorectal Carcinoma: The KRAS/BRAF Pathway

2010

Monoclonal antibodies targeting the epidermal growth factor receptor (EGFR) have improved outcomes for patients with metastatic colorectal carcinoma. Among patients not carrying activating mutations in the KRAS gene, only a limited number will experience tumor response to these therapeutic agents. The role of BRAF mutations in determining resistance to this treatment is emerging through preclinical and clinical studies. Standardization and validation of laboratory mutation analysis is needed to allow an optimal use of anti-EGFR therapies in the management of colorectal carcinoma. Clinical single-arm and randomized studies were conducted both in first-line and refractory settings to evaluate…

Establishing PNB-qPCR for quantifying minimal ctDNA concentrations during tumour resection.

2017

The analysis of blood plasma or serum as a non-invasive alternative to tissue biopsies is a much-pursued goal in cancer research. Various methods and approaches have been presented to determine a patient’s tumour status, chances of survival, and response to therapy from serum or plasma samples. We established PNB-qPCR (Pooled, Nested, WT-Blocking qPCR), a highly specific nested qPCR with various modifications to detect and quantify minute amounts of circulating tumour DNA (ctDNA) from very limited blood plasma samples. PNB-qPCR is a nested qPCR technique combining ARMS primers, blocking primers, LNA probes, and pooling of multiple first round products for sensitive quantification of the sev…

Characterization of a Naturally Occurring Breast Cancer Subset Enriched in Epithelial-to-Mesenchymal Transition and Stem Cell Characteristics

2009

Abstract Metaplastic breast cancers (MBC) are aggressive, chemoresistant tumors characterized by lineage plasticity. To advance understanding of their pathogenesis and relatedness to other breast cancer subtypes, 28 MBCs were compared with common breast cancers using comparative genomic hybridization, transcriptional profiling, and reverse-phase protein arrays and by sequencing for common breast cancer mutations. MBCs showed unique DNA copy number aberrations compared with common breast cancers. PIK3CA mutations were detected in 9 of 19 MBCs (47.4%) versus 80 of 232 hormone receptor–positive cancers (34.5%; P = 0.32), 17 of 75 HER-2–positive samples (22.7%; P = 0.04), 20 of 240 basal-like c…

GAM/ZFp/ZNF512B is central to a gene sensor circuitry involving cell-cycle regulators, TGF beta effectors, Drosha and microRNAs with opposite oncogen…

2010

MicroRNAs (miRNAs) are small regulatory RNAs targeting multiple effectors of cell homeostasis and development, whose malfunctions are associated with major pathologies such as cancer. Herein we show that GAM/ZFp/ZNF512B works within an intricate gene regulatory network involving cell-cycle regulators, TGFβ effectors and oncogenic miRNAs of the miR-17-92 cluster. Thus, GAM impairs the transcriptional activation of the miR-17-92 promoter by c-Myc, downregulates miR-17-92 miRNAs differentially, and limits the activation of genes responsive to TGFβ canonical pathway. In contrast, TGFβ decreases GAM transcripts levels while differentially upregulating miR-17-92 miRNAs. In turn, miR-17, miR-20a a…

Direct Identification of Each Specific Mutation in Codon 12 and 13 of ci-ki-ras2 by SSCP Analysis

1998

We compared the SSCP behaviour of the DNA fragments containing c-ki-ras 2 wild type 12 and 13 codons or each of the 12 possible point mutated sequences in these two codons. We found that a single electrophoresis condition was sufficient to distinguish each specific mutation from the other 11 and from the wild type sequence. This observation makes it possible to identify each specific mutation directly by SSCP without any need for reamplification and sequencing.

DNA damage causes TP53-dependent coupling of self-renewal and senescence pathways in embryonal carcinoma cells.

2013

Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fract…

Polimorfismi del gene Lp(A) e del Locus 9p21 come Fattore di Rischio di malattia coronarica

2012

A large view of CYP21 locus among Sicilians and other Populations: identification of a novel CYP21A2 variant in Sicily.

2011

Background. Several mutations in CYP21 locus cause 21-Hydroxylase Deficiency (21-OHD). The most common mutations are widespread among the different geographic areas and their frequencies have been also reported to differ among certain populations. Aim. To obtain a large view on the frequencies of the most common mutations in the CYP21 locus, in Sicily, in Mediterranean and in other major geographic areas in the worldwide. Subjects and Methods. 308 unrelated CYP21A2 alleles leading 21-OHD in Sicily were genetically typed and compared with other series previously reported in Sicily and in surrounding regions. An analysis of the frequencies of the different geographic areas was also carried ou…